The present invention relates generally to gas generating systems and, more particularly, to gas generators used in vehicle occupant protection systems and related components, such as seatbelt pretensioners.
Gas generators used in seatbelt pretensioners are known as micro gas generators due to the relatively small size of the gas generator. Exemplary pretensioners using such micro gas generators include those described in U.S. Pat. Nos. 6,460,794, 6,505,790, 6,520,443, and 6,419,177, incorporated herein by reference. Micro gas generators generally include an initiator holder for receiving and securing an initiator therein, an initiator including an initiator charge, and a gas generant composition which ignites and bums in response to ignition of the initiator to produce gases for actuating the seatbelt pretensioner.
In addition, conventional micro gas generator designs usually incorporate a casing secured to the initiator holder for containing the gas generant therein and for positioning the gas generant in proximity to the initiator. The casing is secured to the initiator holder by crimping, using deformable crimp tabs machined into the structure of either the holder, or onto the structure of a bore seal affixed to the holder. An O-ring or some other type of compressive seal may also be required to seal the interface between the casing and the initiator holder.
Machining of the crimp tabs along the holder and machining of surfaces along the bore seal for use in securing the casing therealong increase the manufacturing complexity and cost of the initiator holder and bore seal. In addition, existing conventional micro gas generator designs may provide a relatively small bearing surface area along the holder and/or bore seal for use in supporting and securing the bore seal within a pretensioner housing.